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B J Hales

Publications and source records attributed to B J Hales.

At least 19 recordsLinked to original sources
PubMed2006

The chitinase allergens Der p 15 and Der p 18 from Dermatophagoides pteronyssinus.

BACKGROUND: House dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae cause allergic disease in humans as well as in dogs. In geographical regions where the two mite species coexist, they both elicit specific immunoglobulin (Ig E) responses in humans whereas dogs preferentially react to D. farinae extracts. In dogs the main IgE binding is directed to the D. farinae chitinase allergens Der f 15 and Der f 18 and not to the groups 1 and 2 allergens as found for humans. Although the IgE response of humans to Der f 18 has been investigated there is no report on Der f 15-specific IgE in humans. OBJECTIVE: This study aimed to characterize the chitinase allergens Der p 15 and Der p 18 of D. pteronyssinus and to find out whether they are important allergens for humans. METHODS: cDNA was cloned by a polymerase chain reaction strategy from D. pteronyssinus libraries using primers based on conserved chitinase sequences. IgE binding to the recombinant polypeptides was measured by immunosorbent assay. Mice were immunized with the polypeptides and cross-reactivity examined. RESULTS: Two variants of Der p 15 were isolated, encoding mature proteins of 58.8 and 61.4 kDa. The amino acid sequences had 90% identity to Der f 15. The cDNA for Der p 18 encoded a mature protein of 49.2 kDa with 88% sequence identity to Der f 18. Der p 15-specific IgE was detected in 70% and Der p 18-specific IgE in 63% of a panel of 27 human allergic sera. CONCLUSIONS: The D. pteronyssinus chitinases Der p 15 and Der p 18 show a high frequency of binding to IgE in allergic human sera. They are therefore potentially important allergens for humans as well as dogs.

Amino Acid Sequence↗
PubMed2002

Non-allergenic antigen in allergic sensitization: responses to the mite ferritin heavy chain antigen by allergic and non-allergic subjects.

BACKGROUND: The majority of house dust mite proteins are non-allergenic. There is, however, no information on the type of immune responses produced to these proteins and if the responses are affected by allergic sensitization. OBJECTIVE: To identify and produce a non-allergenic antigen of the house dust mite and compare antibody and T cell responses with the responses to allergens in sensitized and non-sensitized individuals. RESULTS: Ferritin heavy chain was cloned from a cDNA library as a candidate non-allergen of the house dust mite. It bound IgG but not IgE in the sera of allergic and non-allergic subjects and induced high T cell proliferative responses that correlated highly with the responses to the major allergen Der p 2. The cytokine response to the non-allergen was characterized by the release of high levels of both Th1 and Th2 cytokines from the PBMC of both allergic and non-allergic subjects. In contrast, the response to Der p 2 showed the expected high level of Th2 cytokine release from the PBMC of allergic subjects, while the Th2 cytokine production from PBMC of non-allergic subjects was low and even lower than that induced by ferritin heavy chain. The levels of IFN-gamma release were similar for all groups. Der p 2 induced significantly more IL-10 than ferritin in the non-allergic group. CONCLUSION: The T cell responses to a non-allergenic protein of the house dust mite were high and strongly correlated with the response to the major allergen. The non-allergenic protein induced high levels of Th1 and Th2 cytokine in both allergic and non-allergic subjects, while the allergen induced high levels of Th2 cytokine in allergic subjects and low levels in non-allergic subjects. The responses to the allergen were thus independently up- and down-regulated with no evidence of bystander regulation.

Adult↗
PubMed2002

T cell cytokine responses to outer membrane proteins of Haemophilus influenzae and the house dust mite allergens Der p 1 in allergic and non-allergic subjects.

BACKGROUND: Haemophilus influenzae are ubiquitous colonizers of the nasopharynx, Little is known about the T cell cytokine responses to the antigens of these bacteria and whether or not the responses may interact with responses to aeroallergen. OBJECTIVE: To measure the T cell cytokine responses to conserved outer membrane protein antigens of Haemophilus influenzae and to house dust mite allergen of subjects allergic to the house dust mite and of subjects without allergic sensitization. METHODS: T cell responses were measured by in vitro proliferation and cytokine release from peripheral blood monocytes (PBMC). The allergen used was Der p 1 and outer membrane proteins were recombinant polypeptides representing the OMP6 and D15 antigens. RESULTS: The PBMC of most subjects had proliferative responses to OMP6 and D15, which were highly correlated. The pattern of cytokine release was Th1 biased with high levels of IFN-gamma and usually little IL-5 or IL-13 although PBMC from a few subjects did release IL-5 independent of allergic status. IL-10 release was readily detected. There was no difference in the anti-OMP cytokine response of PBMC from subjects without any known allergy and the responses of PBMC from subjects who were highly allergic to house dust mite. The responses to the Der p 1 allergen showed the expected Th2 cytokine release. CONCLUSION: The outer membrane protein antigens of the ubiquitous colonizing bacteria Haemophilus influenzae induce Th1 cytokine responses which are similar for PBMC from non-allergic individuals and subjects with a high degree of allergy to the perennial house dust mite allergen and strong Th2 responses to Der p 1.

Adult↗
PubMed2002

Genetic variation of Der p 2 allergens: effects on T cell responses and immunoglobulin E binding.

BACKGROUND: Der p 2 is a highly polymorphic allergen that shows a distinct pattern of sequence divergence. The effect of the variations on T cell and antibody responses has not been compared. OBJECTIVES: To compare IgE antibody binding and T cell proliferation and cytokine release induced by variants of Der p 2. METHODS: Peripheral blood mononuclear cells (PBMC) from 19 allergic and 15 non-allergic people were stimulated with recombinant variants of Der p 2. IL-5, IL-10, IL-13 and IFN-gamma were measured by a time resolved fluorescence (TRF) assay. Serum IgE antibody was measured using a solid-phase TRF assay. RESULTS: Overall the most prevalent variant of Der p 2 (Der p 2. 0101) was the highest or approximately equal highest inducer of T cell proliferation and IL-5, IL-10, IL-13 and IFN-gamma release. The most divergent variant 0104 induced the next highest responses. The variants 0107 and 0108 showed interesting changes especially when the allergic status was considered. Responses to 0107 showed poor Th1/Th2 polarization and, except for IL-10 release, cytokine responses to 0108 were low for non-allergic subjects. The variant 0101 showed similar monoclonal antibody binding but moderately less IgE binding than the other variants. CONCLUSIONS: The most prevalent variant, Der p 2. 0101, was the most active for T cell stimulation and although its IgE binding was slightly less than other variants that was highly correlated. The variant Der p 2. 0104 which contains the known common polymorphic changes had a response which was similar to Der p 2. 0101 and thus these two variants were the most stimulatory representations of Der p 2. The T cell responses to the less common variants 0107 and 0108 however, showed consistent differences demonstrating that changes in the sequence could change the cytokine response.

Adult↗
PubMed2001

Mechanistic features and structure of the nitrogenase alpha-Gln195 MoFe protein.

EPR signals observed under CO and C(2)H(2) during nitrogenase turnover were investigated for the alpha-Gln(195) MoFe protein, an altered form for which the alpha-His(195) residue has been substituted by glutamine. Under CO, samples show S = 1/2 hi- and lo-CO EPR signals identical to those recognized for the wild-type protein, whereas the S = 3/2 signals generated under high CO/high flux conditions differ. Previous work has revealed that the EPR spectrum generated under C(2)H(2) exhibits a signal (S(EPR1)) originating from the FeMo-cofactor having two or more bound C(2)H(2) adducts and a second signal (S(EPR2)) arising from a radical species [Sørlie, M., Christiansen, J., Dean, D. R., and Hales, B. J. (1999) J. Am. Chem. Soc. 121, 9457-9458]. Pressure-dependent studies show that the intensity of these signals has a sigmoidal dependency at low pressures and maximized at 0.1 atm C(2)H(2) with a subsequent decrease in steady-state intensity at higher pressures. Analogous signals are not recognized for the wild-type MoFe protein. Analysis of the principal g-factors of S(EPR2) suggests that it either represents an unusual metal cluster or is a carboxylate centered radical possibly originating from homocitrate. Both S(EPR1) and S(EPR2) exhibit similar relaxation properties that are atypical for S = 1/2 signals originating from Fe-S clusters or radicals and indicate a coupled relaxation pathway. The alpha-Gln(195) MoFe protein also exhibits these signals when incubated under turnover conditions in the presence of C(2)H(4). Under these conditions, additional inflections in the g 4-6 region assigned to ground-state transitions of an S = 3/2 spin system are also recognized and assigned to turnover states of the MoFe protein without C(2)H(4) bound. The structure of alpha-Gln(195) was crystallographically determined and found to be virtually identical to that of the wild-type MoFe protein except for replacement of an NuH-S hydrogen bond interaction between FeMo-cofactor and the imidazole side chain of alpha-His(195) by an analogous interaction involving Gln.

Amino Acid Substitution↗
PubMed2001

Allergens of wild house dust mites: environmental Der p 1 and Der p 2 sequence polymorphisms.

BACKGROUND: Sequence diversity is a common feature of mite allergens. Previous studies, using predominantly commercial mite clones, have described several polymorphic residues for Der p 1 and Der p 2. OBJECTIVE: This study aimed at determining the occurrence of sequence diversity in environmental mite isolates. METHODS: Mites were isolated from houses in Perth and Sydney, Australia. Total RNA was extracted from 1 to 30 Perth mites, and cDNA was synthesized by reverse transcriptase PCR. Der p 1 and Der p 2 cDNAs were PCR amplified and sequenced. Genomic Der p 1 DNA was amplified from whole Sydney mites directly by PCR and then sequenced. RESULTS: Twelve Der p 1 and 9 Der p 2 cDNA clones and 3 Der p 1 genomic DNA were analyzed and showed a high frequency of amino acid polymorphisms. Der p 2 displayed a clear pattern of divergence toward 2 alleles that differed by 4 amino acids and had characteristic silent nucleotide changes. The pattern for Der p 1 was different and unusual, with almost no silent nucleotide substitutions but frequent sporadic missense changes. Proliferative responses of peripheral blood mononuclear cells to peptides containing polymorphic residues of Der p 1 were detected in 8 of 19 subjects, with stimulation being found only for either one of the variant forms of the peptides. However, the responses to variants of whole recombinant allergens were similar, as shown for 4 variants of Der p 2. CONCLUSION: Two clones for each of the allergens were identified as containing sequences that were largely representative of environmental isolates. A small-scale reverse transcriptase PCR used to produce cDNA from individual mites isolated from house dust will have wide application for studies on mite genetics and the production of recombinant mite allergens. Differences in T-cell responses to peptides representing variant epitopes were found, but responses to variants of whole recombinant allergens were similar. The GenBank and Swiss Prot database entries for Der p 1 (U11695) and Der p 2 (P49278) have been updated with the inclusion of the sequence polymorphisms described in this study.

Animals↗
PubMed2000

Cross-reactivity of T-cell responses to Dermatophagoides pteronyssinus and D. farinae. Studies with group 1 and 7 allergens.

BACKGROUND: Comparative information on T-cell responses to allergens from different Dermatophagoides species is limited even though differences in the epitypic recognition have been described. OBJECTIVE: To compare the level of T-cell proliferation and cytokine production to allergens from the mite species, D. pteronyssinus and D. farinae. METHODS: Freshly isolated peripheral blood mononuclear cells (PBMC) from house dust mite (HDM)-allergic and HDM-nonallergic donors were stimulated with the group 1 and group 7 allergens of D. pteronyssinus and D. farinae and the level of proliferation as well as IL-5 and IFNgamma production were measured. RESULTS: The proliferative response and the level of IL-5 produced after in vitro challenge with group 1 and group 7 allergens were equivalent for the allergens from both mite species even though D. farinae is not detected in the environment where the study population live. As expected the level of IL-5 production to the individual allergens was higher for the allergic donor group than for the nonallergic donors, however, there was no difference in the level of T-cell proliferation between the different donor groups. CONCLUSION: The proliferative and cytokine response to the group 1 and group 7 allergens for D. pteronyssinus and D. farinae indicates that there is a large degree of T-cell cross-reactivity between the whole purified allergens from each species. This is despite previous reports demonstrating different responses to synthetic peptides representing Der p 1 and Der f 1 in a similar study population.

Adult↗
PubMed2000

Cytokine responses to Der p 1 and Der p 7: house dust mite allergens with different IgE-binding activities.

BACKGROUND: There is very limited information comparing T-cell responses to different house dust mite (HDM) allergens even though T cells are essential in the initiation and regulation of immunoglobulin (Ig) E synthesis and eosinophilia. OBJECTIVE: To compare the level of T-cell proliferation and cytokine production to the group 1 and group 7 HDM allergens which are known to have different IgE-binding capabilities. METHODS: Freshly isolated peripheral blood mononuclear cells (PBMC) from HDM-allergic and HDM-nonallergic donors were stimulated with the group 1 and group 7 allergens of Dermatophagoides pteronyssinus and the level of proliferation as well as IL-5 and IFNgamma production were measured. RESULTS: The proliferative and IL-5 production to the group 1 and group 7 allergens were equivalent despite the group 7 allergen's lower frequency of IgE-binding. However more IFNgamma was produced to Der p 7 than to Der p 1, particularly for the nonallergic donors. As expected IL-5 production was much higher for PBMC from the allergic donors than for cells from nonallergics; however, there was no difference in the level of T-cell proliferation between the donor groups. CONCLUSION: The relative importance of the individual HDM allergens is normally determined by measuring the frequency of IgE-binding to the allergen in sera from an allergic population. The equivalent increased IL-5 response of PBMC from allergic people to the group 1 and group 7 allergens despite the different IgE-inducing activity indicates that these allergens may be equally capable of contributing to an asthmatic response by inducing eosinophilia.

Adult↗
PubMed1998

Investigation of CO binding and release from Mo-nitrogenase during catalytic turnover.

During enzymatic turnover in the presence of CO, Mo-nitrogenase has been shown to generate two different EPR signals termed lo-CO (PCO = 0.08 atm) and hi-CO (PCO = 0.5 atm). When the formation of hi-CO is monitored under the conditions of very low electron flux, a 2 min lag is observed prior to the initial detection of the signal followed by a near-linear rate of formation during which the S = 3/2 cofactor signal exhibits similar decay kinetics. Increasing the electron flux produces a significant increase in the rate of both the formation of hi-CO and the decay of the S = 3/2 cofactor. These results are interpreted in terms of a state of the enzyme (redox or structural) generated only during turnover which is needed to initially bind CO to the cofactor. Under high electron flux conditions, new EPR inflections are observed at g = 5.78, 5.15 and g = 1.95, 1.81 and tentatively assigned to S = 3/2 and 1/2 states of the CO-bound cofactor and 1 equiv of oxidized P cluster, respectively. Sudden removal of CO from the environment results in the slow decay (>10 min) of both the hi-CO signal and CO inhibition of acetylene reduction activity. The use of ethylene glycol to quench enzymatic activity strongly inhibits the decay of hi-CO (in the presence of CO) and the subsequent decay of lo-CO (after removal of CO) but does not prevent the reversible interconversion hi-CO left and right arrow lo-CO + CO.

Adenosine Triphosphate↗
PubMed1998

House dust mite allergen characterisation: implications for T-cell responses and immunotherapy.

T cells are central regulators and mediators of allergic sensitisation and disease. The house dust mite allergens are a biochemically diverse group of proteins which are present in extracts and the environment in a wide range of concentrations. Here the importance of ascertaining the contribution of the different allergens to Th2 lymphokine production and the development of allergy is discussed as well as the effect of allelic polymorphisms and inter-species sequence diversity on T-cell activation. The imbalances in allergen concentrations in commercial extracts, the sequence variations from allergens in the environment and the poor discrimination of allergy due to different mite species points to areas of improvement and the development of novel immunotherapeutic strategies and reagents.

Alleles↗
PubMed1997

T-cell sensitization to epitopes from the house dust mites Dermatophagoides pteronyssinus and Euroglyphus maynei.

BACKGROUND: Dermatophagoides pteronyssinus and Euroglyphus maynei frequently occur in house dust but little is known about primary sensitization to the less abundant E. maynei. OBJECTIVE: To determine the occurrence of primary sensitization to E. maynei by T-cell responses and the crossreactivity to D. pteronyssinus. METHODS: The proliferative response of peripheral blood cells to overlapping peptides from Der p 1 and Eur m 1 were measured as well as to peptides from Der f 1, an allergen not found in the study environment. RESULTS: The most frequent and strongest responses were to Der p 1 peptides especially in the region 105-133. However, 3/17 responders to mite peptides were stimulated predominantly by Eur m 1 peptides and a further two had their highest response to an Eur m 1 peptide. There was very little crossreactivity between Der p 1 and Eur m 1 peptides and very little response to peptides from Der f 1. CONCLUSION: E. maynei group 1 allergens are a significant source of primary T-cell sensitization and have little T-cell crossreactivity with D. pteronyssinus or D. farinae.

Adult↗
PubMed1996

Isolation of two forms of the nitrogenase VFe protein from Azotobacter vinelandii.

When Q-Sepharose was used in the purification of the V nitrogenase proteins from Azotobacter vinelandii, an increase in resolution was observed that resulted in a separation of the nitrogenase component 1 protein (Av1') into two forms, labeled Av1'A and Av1'B. Even though both forms possessed the same enzymatic behavior, Av1'A exhibited a lower specific activity and migrated during gel filtration with an apparent lower molecular weight than Av1'B. Furthermore, SDS-polyacrylamide gel electrophoresis showed different relative compositions of the two major subunits of both forms, with Av1'A possessing a trimer (alpha beta 2) pattern compared to the more typical tetramer (alpha 2 beta 2) pattern found for Av1'B. Metal analysis indicated a V-to-Fe ratio of 1:19 for Av1'A and 1:15 (or 2:30) for Av1'B, while acid-labile sulfide analysis showed that Av1'A possessed about half as much sulfide as Av1'B. EPR spectroscopy revealed that both proteins retained the S = 3/2 and S = 1/2 signals observed in earlier isolations, with an additional S = 1/2 signal present in the spectrum of protein A. These results suggest that Av1'A is an incomplete form of the VFe protein, containing only one cofactor and one P cluster with an additional [Fe4-S4]-like cluster. The presence of a V storage protein in A. vinelandii was also investigated. Although no V storage protein was found, two V-binding proteins were observed.

Azotobacter vinelandii↗
PubMed1996

Oxidative titration of the nitrogenase VFe protein from Azotobacter vinelandii: an example of redox-gated electron flow.

The nitrogenase VFe protein of Azotobacter vinelandii (Av1') has been shown to exist in two forms called Av1'A, which has a primary alpha beta 2 trimeric structure, and Av1'B, which has an alpha 2 beta 2 tetrameric structure [Blanchard, C. Z., & Hales, B. J. (1996) Biochemistry 35, 472-478]. Both forms exhibit S = 5/2 EPR signals in the as-isolated state that may be assigned to 1-equiv-oxidized P clusters (P+). These signals are abolished by enzymatic reduction with the component 2 protein (Av2'). Stepwise oxidative titrations of enzymatically reduced Av1'B result in the restoration of the S = 5/2 P+ signals and the concurrent decrease of the S = 3/2 vanadium cofactor signal. Further oxidation results in the appearance of an integer spin signal assigned to the 2-equiv-oxidized P cluster (P2+). Unlike the analogous signal previously observed in Mo nitrogenase component 1 (Av1), which arises from an excited state, the integer spin P2+ signal in Av1'B originates from a ground-state doublet. Similar oxidative titrations of enzymatically reduced Av1'A show redox behavior dramatically different from that of Av1'B, as monitored by EPR spectroscopy. We observed spectral evidence for a redox-induced intramolecular electron transfer between the reduced P cluster and the oxidized FeV cofactor cluster during the titrations.

Azotobacter vinelandii↗
PubMed1995

Inhalant allergen-specific T-cell reactivity is detectable in close to 100% of atopic and normal individuals: covert responses are unmasked by serum-free medium.

BACKGROUND: It is widely held that in vitro T cell responses to allergens are more prominent in atopic than in normal individuals, though this conclusion is based upon culture techniques which fail to detect proliferative responses in a significant minority of atopics and many normals. OBJECTIVES: Study allergen-specific proliferative responses of T cells cultured in serum-free medium (SFM). Examine associations between atopic status, age and T cell reactivity. METHODS: Initially, peripheral blood mononuclear cells were stimulated with allergens or antigens in SFM, and compared with cells cultured in RPMI + 10% fetal calf serum or human AB serum. Subsequently, T cell reactivity was studied in 34 adults (20-49 years), 27 children (2-13 years), and 19 infants (< or = 10 weeks) using SFM alone. RESULTS: Compared with serum-supplemented medium, SFM enhanced net T cell proliferation, both in bulk culture and when cloning at limiting dilution. In many subjects, SFM unmasked T cell reactivity to allergens which was not otherwise evident, and lowered the threshold allergen levels required for in vitro T cell triggering. For most allergens, T cell proliferative responses did not differ between adults who had specific IgE, and those who did not. The most vigorous responses observed were to ubiquitous inhalant allergens, which stimulated T cells from close to 100% of adults and children, and over 60% of infants. In contrast, responses to the 'vaccine' antigen tetanus toxoid were completely absent in the latter age group, but present in the majority of adults and children. CONCLUSIONS: These findings suggest that the extent of active T cell recognition of environmental allergens has been hitherto underestimated, and further that these responses may frequently be initiated in very early life. Additionally, these findings reinforce the notion that qualitative (as opposed to quantitative) variations in specific T cell reactivity ultimately determine allergen responder phenotype.

Adult↗
PubMed1994

Mössbauer characterization of the metal clusters in Azotobacter vinelandii nitrogenase VFe protein.

The VFe protein of alternative nitrogenase, isolated from Azotobacter vinelandii, strain LS15 and designated as Av1', has been investigated by Mössbauer spectroscopy. The Mössbauer spectrum of the dithionite-reduced Av1', recorded at 4.2 K with a 60-millitesla magnetic field applied parallel to the gamma-beam, is a superposition of three spectral components: 1) a complex spectrum (the M component) with magnetic hyperfine structures attributed to the paramagnetic FeV cofactor, 2) a component (the P component) consisting of three quadrupole doublets identifiable as the Fe2+, D, and S doublets similar to those observed for the P cluster pairs in MoFe proteins, and 3) a minor (4% of total absorption) quadrupole doublet attributable to adventitiously bound iron. The observed 4.2-K parameters for the Fe2+ (delta EQ = 2.99 mm/s and delta = 0.64 mm/s), D (delta EQ = 0.75 mm/s and delta = 0.63 mm/s), and S (delta EQ = 1.2 mm/s and delta = 0.65 mm/s) iron sites and their temperature dependence are very similar to those observed for the P cluster pairs in the conventional MoFe proteins. Similar to those of the MoFe protein, strong field spectra indicate that these doublets are associated with a diamagnetic system. Their percent absorption intensities (Fe(2+)/D/S = 13.0:32.2:6.8) determined at 4.2 K after the removal of the contributions from the adventitiously bound iron are comparable to those of the P cluster pairs in MoFe proteins. These observations established that Av1' also contains P cluster pairs that are identical, in both composition and quantity, to those of the MoFe proteins; i.e. each molecule contains two P cluster pairs and each pair is formed by two Fe2+, five D, and one S iron sites. Considering that 52% absorption of the P component corresponding to two 8Fe clusters, the remaining 48% absorption determined for the M component is consistent with two 7Fe-containing FeV cofactors/molecule of Av1'. The fact that both P cluster pairs are found in the diamagnetic states implies that the S = 3/2 and S = 1/2 signals detected in earlier EPR measurements are associated with the FeV cofactor and suggests a spin mixture for the FeV cofactor in the dithionite-reduced Av1'.

Azotobacter vinelandii↗
PubMed1994

The nature of the copper ions in the membranes containing the particulate methane monooxygenase from Methylococcus capsulatus (Bath).

It is shown that the particulate methane monooxygenase (pMMO) has an obligate requirement for copper. The MMO activity in the particulate fractions obtained from Methylococcus capsulatus (Bath) cells is found to increase with increasing copper content of the membranes. The enzyme activity from membranes obtained from cells grown at low copper levels can be stimulated further by the addition of Cu(II) ions to the assay medium. The membrane-bound copper ions can exist in both Cu(II) and Cu(I) forms. EPR and magnetic susceptibility characterizations of the membranes indicate the presence of an exchange-coupled trinuclear Cu(II) cluster when the bulk of the copper ions is oxidized. However, the functional form of the enzyme is the reduced or partially reduced form. The copper ions in the membrane fractions as isolated often exhibit a high level of reduction. An EPR spectrum with one unpaired electron spin delocalized over three copper nuclei has been observed for the two-electron reduced trinuclear copper cluster. The high correlation between the copper level in the membranes and enzymatic activity as well as the high reactivity of the reduced copper clusters toward dioxygen strongly indicate that the membrane-bound copper ions constitute the active sites of the pMMO.

Cell Membrane↗